Expect to hear the Phoenix Suns emphasize defense first during Summer League, and know that’s the right move for a positionless, versatile roster of youngsters who will be able to contribute to their regular season squad if they lean upon those offseason lessons.

Also know that the Suns will not be relevant, good or even average unless their shooting improves.

Phoenix, one of the fastest teams in the league, fits into the run-and-gun stereotype.

These days the NBA is more nuanced; it’s about pace and space. The Suns’ starting lineup from 2016-17 is likely to be unchanged this October, and it doesn’t have the latter.

The lack of catch-and-shoot attempts is important because even misses will lead opponents to at least consider it a threat. That Phoenix rarely hit open and catch-and-shoot jumpers only exacerbated the willingness of opponents to close out and perhaps risk their defense breaking down.

Throw in the fact that the Suns shot below 34 percent from the corners — a shot that can make weakside, overhelping defenders think twice about leaving their man — and that leads to more problems.

What’s the solution?

Since Phoenix didn’t add a shooter this offseason other than second-round pick Davon Reed, it needs to develop some from its young core.

Is that a concerning thing to bet on?

Booker’s pretty stroke hasn’t translated to anything more than average three-point shooting since he became the No. 1 option, and only seldom-used Jared Dudley could be considered strong beyond the arc. Bledsoe’s tiny improvements bring promise, but his discomfort catching and shooting hurts.

Warren regressed last year in a big way, and rookie Josh Jackson’s wonky release overshadows the decent 38-percent clip he shot last year at Kansas. Maybe the most hope comes from power forwards Dragan Bender and Chriss, who both have been trying to sell themselves as three-point shooters despite shooting below 33 percent in their rookie years.

The good news for the Suns is that they need just a key rotation player or two to make the spacing much improved.

Even adding an average shooter will help. For example, swapping out Warren (27 percent from three) for P.J. Tucker (36 percent) last year improved the starting group’s spacing drastically, enough to move Phoenix into the middle of the bottom half of those 60 lineups Sciria included.

Maybe the most recent poster boy the Suns’ youngsters should model their development after is Otto Porter, who is set to receive a max contract heading into his fifth season.

Despite shooting 42 percent from college three-point line as a sophomore, he struggled initially in the NBA, shooting 19 percent from three as a rookie and 34 percent in his second year. That only improved to 37 percent his third season and 43 percent last year.

Otto Porter may not win MIP this season but he's shown rapid improvement every year he's been in the league. pic.twitter.com/BekcSwjHou

Call that the Kawhi Leonard level of improvement. It’s hardly a given.

Phoenix has built a young core of players who can switch on defense and use their skillsets to create mismatches on offense.

The lack of major offseason additions has garnered hope that patience is the most important virtue in the Valley. Yet, that lack of change also means one of the biggest flaws of the Suns’ roster has not been addressed.

But until one or two of the young core members become reliable three-point threats, how they fit together offensively remains hard to see.